Rice Irrigation Options

Growing Rice with Center Pivots and Linears

It's time for a change. Traditionally, farmers use flood irrigation to grow rice, a method that requires a huge amount of water. While this practice has proven successful for centuries, growers like you are continuously looking for ways to become more profitable in crop production.

In 2007, we began our rice irrigation program. Research by Valley® Irrigation and our various partners focused on two distinct groups of farmers looking for more profitable rice production through center pivots and linears: (1) traditional rice growers who want to conserve water and decrease flood costs, and (2) first-time rice growers looking for a profitable rotational crop that can be grown on a non-traditional rice field.

We've gathered the benefits, research, and other information here to help you make the transition to more efficient and profitable rice production.

Center pivot data from trials conducted in 2010 in the USA. Flood data from the University of Arkansas. Archie Flanders, et al. 2010 Crop Enterprise Budgets, December 2009.

Identifying rice characteristics is an important part of the Valley Irrigation production process for growing rice under mechanized irrigation.

Properly selecting your rice, either variety or hybrid, is a critical step in maximizing potential with mechanized irrigation. So far, we have focused on long-grain hybrids and some aromatic varieties. Research on variety and hybrid performance under mechanized irrigation is currently being conducted by RiceTec, the University of Missouri Delta Research Center, EMBRAPA, and IRGA.

Researchers suggest that growers look for the following key characteristics in rice:

Disease resistance (especially to blast)

Strong tillering

Hardy root system

Other important characteristics include:

Milling quality

Yield potential

Standability/lodging score

Meeting crop nutrient needs is an important part of the production process for growing rice under mechanized irrigation, which was developed by Valley irrigation.

We recommend periodic soil sampling and testing to determine crop nutrient needs. Because mechanized irrigation minimizes the potential for runoff and/or leaching, it is superior to traditional rice management methods. You have the ability to supply crop inputs (dry or liquid) through a center pivot or linear, saving the expense of aerial fertigation. If needed, phosphorus and potassium are typically applied by ground application prior to planting.

Current research focuses on supplying crop nitrogen needs through a center pivot or linear. By using mechanized irrigation, nitrogen can be applied frequently to achieve maximum efficiency of its use.

Research

Dr. Gene Stevens' team at the University of Missouri Delta Research Center has conducted the most research of any Valley rice partner on crop nutrient needs. To read more about Dr. Stevens' breakthroughs in using nitrogen with mechanize irrigated rice, please click here.

Irrigation Management

Irrigation management is a key factor the Valley Irrigation rice production process. We are conducting research to develop a commercially-viable solution. Both field-plot and field-scale trials are being overseen.

How is irrigation management with mechanized irrigation different from flood?

Under a pivot or linear, growers just need to satisfy the crop water needs. The primary purpose of flooding a field is weed control.

Because the irrigation is precision mechanized, growers will attain maximum uniformity across the field.

How is mechanized irrigation management for rice different than typical row crop irrigation?

Growers have to manage differently due to the shallow rice root system, which requires lighter, more frequent applications.

Irrigation Scheduling Methods

Water balance method: measure and observe today's soil moisture and ET, and make an irrigation decision based on how much water is needed to satisfy ET

Scheduling model: IrriSimple (Brazil), IrriExcel (Arkansas, USA)

Monitor soil moisture: Irrometer Watermarks, feel method, etc.

Combination of above

Irrigation scheduling methods used are based on personal preference.

Wheel Track Solutions

Wheel track solutions are an integral part of the Valley Irrigation production process for growing rice under mechanized irrigation. Wheel track issues cannot be completely resolved with just hardware or just management; it requires a combination of the two. A correct solution is dependent upon the soil texture and field topography. Valley Irrigation can provide recommendations for a specific situation.

Hardware

Drive unit:

Tire sizes, such as 14.9 x 24, 18.4 x 26, etc.

Flotation options, such as Valley 3-Wheel Drive, Track Drive, etc.

Sprinkler package:

Proper package based on climatic and soil conditions, tillage practices, and topography

Strong consideration should be given to dry wheel track options, such as 180 degree spray nozzles at drive unit, boom backs, etc.

Management

You need to balance crop water needs with drying wheel tracks between applications

Many times, lighter, more frequent applications will meet this goal

Valley Irrigation recommends using some type of irrigation scheduling program

You should apply water so that the soil profile is not completely saturated and thus enables runoff

Frequently Asked Questions

For more than 20 years, several growers across the world have tried producing rice under center pivots and linears. However, the net return from the field did not meet expectations. Valley Irrigation conducted extensive research to identify and develop production guidelines to help farmers meet their economic expectations and provide a secure, efficient, and cost-saving option for growing rice under mechanized irrigation.

About the Project

What is Valley Irrigation doing to support rice under mechanized irrigation?

In 2008, a team of dedicated personnel was created. This team conducted research, multiple worldwide trials and field-scale studies; provided technical information to growers; and developed educational and marketing materials, such as the Valley Irrigation Rice Production Guide.

Mechanized Irrigation and Management

What is a center pivot?
A center pivot is a precision, mechanized irrigation machine that irrigates a field in a circle. The spans of a center pivot revolve around a central pivot point. Valmont Industries manufactured the industry's first center pivot mechanized irrigation machine in 1954. Use of a center pivot can result in a reduction in operating costs, a quick return on your initial investment, and the conservation of resources.

What is a linear machine?
A linear machine is similar to a center pivot, except that it moves up and down a field.; it is perfect for a square or rectangular field. Linears can achieve up to 98 percent field coverage and use water from either a canal/ditch or pipeline. A linear does not revolve around a central pivot point, rather its spans are attached to a moving cart.

How much water will be required for a center pivot to supply the necessary amount of water for rice production?
In the Valley rice fields, we have consistently achieved a water savings of 50 percent or more over traditional flood irrigation. The actual water required is dependent upon the climatic conditions and soils of your field.

I am not familiar with irrigation management and scheduling for pivots, I am only familiar with flooding. How will I manage and schedule irrigation?
Irrigation management and scheduling is very similar to how one would manage center pivots or linears on other cereal or row crops. Valley Irrigation, in conjunction with universities and research groups, has been using several methods to develop guidelines. Methods include manual soil probe, soil moisture sensors, and computer models.

What do I do about corners and other areas of the field I cannot irrigate with a center pivot?
Valley Irrigation offers a number of solutions to maximize the rice production area in any field, such as towable pivots, corner arms, and linears.

If it is typical to make more rotations to irrigate rice, are there more maintenance requirements?
As with any piece of farm equipment, maintenance is required. Center pivots and linears are designed to be economically operated for 20,000 hours or more. Most maintenance is based on monthly or annual time rather than operating hours.

How late into the season does rice need to be irrigated with center pivots?
This is an area requiring more study. You will probably apply water through the pivot or linear later in the season than you would for flooded fields, but that is because it can take two to three weeks to drain a flooded rice field. Even with these additional applications of water, you can still realize a 50 percent water savings over what is pumped into a flooded field. The findings from our 2009 trials indicate that you need to take the crop growth stage and soil type into consideration when determining when to stop applying water.

Rice Varieties and Hybrids

Will I be able to grow rice varieties I am familiar with under center pivots and linears?
You can, but you may want to consider other options, as well. The varieties you use under flood irrigation can be used under center pivots, but some will adapt to the different growing environment better than others, presenting you with the potential for higher economic returns. There are some specific seed characteristics we look for when choosing what to grow under mechanized irrigation, among those are vigorous tillering and blast resistance.

Can I grow rice two years in a row?
You can grow rice after rice, however, crop rotation is advised, just as it is with every other crop. Every monoculture system (rice after rice, soybeans after soybeans) imposes several factors that will limit higher yields. In the case of rice, noticeable reductions in yields are observed after the third year of growing rice after rice.

Will I be able to produce the same yields and profits if I grow rice under center pivots?
With today's advancements in crop technology, there is no reason to assume you cannot produce the same rice yields under center pivots and linears as you can with flood irrigation. However, it is not unreasonable to experience a slight drop in yields the first year or two when using mechanized irrigation. This is mainly due to your need to adjust to a new growing system. Despite the drop in yields, you can still find yourself more profitable than with flood irrigation due to the overall lower production costs.

Pests and Diseases

Will I have more or fewer problems with red rice if I produce rice under mechanized irrigation?
After two or three years of growing rice under center pivots or linears, as well as using a crop rotation scheme and no-tillage system, you are likely to observe reductions in your previously infested rice fields.

What are the major pest and disease concerns when producing rice under center pivots and linears?

The pests commonly experienced with flooded rice may also be an issue in mechanized irrigated fields. In our experience in Brazil, USA, and Pakistan, no pest differences have been seen between flood and pivot-irrigated rice. There are some diseases, however, that will require attention, such as rice blast, brown spot, and sheaf blight. Typically, there is a higher potential for blast to develop in a rice field under mechanized irrigation and less potential for sheaf blight. In field experience, the brown spot has been about the same. Choosing the right seed with resistance, as well as being prepared to apply a preventative fungicide application at the appropriate time will greatly assist in disease management.

Do light, more frequent applications of water promote more disease?

The goal of the Valley Irrigation rice program is to try to ensure the crop canopy has a chance to dry out between applications, including the soil surface. The micro climate in the rice may actually be less humid using mechanized irrigation than in a flooded field.

I flood my field primarily for weed control. Won't I have a bigger issue with weed control if I grow my rice under a center pivot or linear machine?
Flood irrigation is all about controlling many weed species. However, there are some weeds that thrive under a flooded environment, such as red rice. Under mechanized irrigation, more weed species may be observed due to the absence of standing water, but the severity of infestation can be reduced by good management and, in most cases, the management is very similar to what is done under flood irrigation.

Rice Production Guide

The process of growing rice with center pivots, linears, and corner machines is patented by Valley Irrigation. This copy of the Valley Rice Production Guide is a royalty free license to use this process to grow rice.

Your Local Valley Dealer

Only your local Valley dealer can give you the best advice on which irrigation equipment and options are right for you. Find your dealer today!